Ion trap and method of making it



March 13, 1951 B. M. NASE ION TRAP AND METHOD OF MAKING IT 2 Sheets-Sheet 1 Filed June 14, 1947 ATTORNEYS Y manufacture of ion vion trap and its mounting ing operation, an

gun. the pair of angular relation vention, reference is made drawings, in which:

, used inthe preferred spending with the Patented Mar. 13, 1951 UNITED STATES PATENT OFFICE 2,544,934 ION TRAP AND METHOD OF G IT Benjamin perior Tube M. Nase, Lederach, Pa., assignor to 511- Company, Norristown, Pa., a corporation of Pennsylvania Application June 14, 1947, Serial No. 754,729

1 5 Glaims. (Cl. 250-275) This invention relates to electrodes for the electron guns of cathode ray tubes, and is particularly concerned with the construction and traps employed to prevent disintegration or blackening of the fluorescent screen coating by ion bombardment.

In accordance with the present invention, an rings are formed from a single sleeve or tube whose ends are flared or rolled. preferably after a preliminary chamfering operation, to

form the mounting rings, and which is thereafter dia onally severed intermediate its ends to form a pair of, electrodes jointly forming an ion trap. Preferably before the sleeve is severed, or at least before its release from a clamp holding it during the severalignment mark or scratch is made longitudinally thereof, so that in subsequent assembly of the electrodes in an electron them may be brought into proper to leave between them for proper ion trapping action a diagonal slot of constant Width.

The invention further resides in the ion trap and themethod of making it herein described and claimed.

For a more detailed understanding of the into the accompanying Figs'l to 4 illustrate an ion trap at successive stages of its formation from cylindrical stock;

Fig. 5 is a sectional view illustrating the step of forming the mounting rings;

Fig. dis a perspective view of clamping blocks method of forming the ion traps;

Fig. 7, in perspective, illustrates the step of diagonally severing the sleeve to form a pair of ion-trap electrodes;

Fig. 8 is a sectional view showing the incorp'oration of the ion trap electrodes in an electron gun assembly;

Fig. 9 is a fragmentary detail view on enlarged scale of parts appearing in Fig. 8; r

Fig. 1D is an exploded view of the components ofone-half of the ion-trap assembly; and g the ion-trap' Fig. ll is a perspective view of assembly.

Referring to Fig. 1, the sleeve 10 is cut from thin walled metal tubing of diameter corredesired diameter of the-finished ion-trap electrodes. The ends thereof are slightly internally chamfered as indicated at H for reason which later appear. The cutting and chamfe'ring operations may be performed on a positioned between the and .I3,

'p'osite ends of which are ,by. semi-circular grooves lathe having a hollow spindle suited to passa length of tubular stock having. beyond the chuck at the forward end of the spindle, a projecting portion or tip to be cut off to form a sleeve I0. One end of the sleeve may be chamfered before it is severed from the parent stock.

At the next stage or station, a sleeve i0 is pair of forming dies 12 Fig. 5, one or both of which may be moved in direction axially of the sleeve, the oprespectively received posed faces of the dies. The inner diameter of .eachof the grooves corresponds with the inner diameter of the sleeve. Preferably, for ease in alignment of the sleeve, the central portions Hi, I

ll of the dies bounded by the grooves extend an appreciable distance in frofit of the corresponding die face. As the dies l2, l3 are moved toward one another, the ends of the sleeve ID are each forced outwardly and then back to form a peripheral flange or bead to be used in mounting of the electrodes formed from the sleeve.

The internal chamfering of the sleeve at its opposite ends facilitates the flaring of the ends of screws or by their rotation or axial movement.

thetubes during the formation of the beads l8.

Upon completion of this step, the sleeve has the appearance and is of the construction or configuration shown in Fig. 2. v

The partially formed electrode structure is then disposed between a pair of clamping blocks l9, l9, Figs. 6 and 7, with the beads or rings l8 of the electrode structure nesting in the rounded grooves 2B, 2!, Fig. 6, spaced longitudinally of the bore or opening 22, Fig. 7, formed by the complementary semi-circular recesses 23, 23, Fig. 6, of the pair of blocks.

The diameter of the bore 22 corresponds with the external diameter of sleeve 10 and the pairs of grooves 20, 20 and 2|, 2| snugly fit the rings l8, [8 at the ends of the sleeve. With the flanged sleeve in position between them, the blocks I9, l9 are held together as by clamping disposition in a vice or clamp, firmly to hold the sleeve l0 and soprevent its The upper faces I of the blocks H! are provided with complementary notches 24 located between the grooves 20, 2 l and extending through the upper faces of the blocks to the recesses 23, thus to expose a longitudinal section of the sleeve. While the sleeve is firmly held by the blocks, a mark or scratch 25 is made longitudinally thereof, Figs. 3 and 4, by insertion of a scribing tool, or equivalent, through the slot formed by the notches 24, 24, the

l4 and H5 in the op-.

released by unclamping of the blocks burrs or rough edges caused by the sawing may I 9, an apertured disk ring if and the grooved portions 30 of the associated sides of the slot serving as a straight edge or guide for the marking tool.

This marking step is performed preferably before the sleeve is diagonally cut, as later de scribed, or in any event before the sleeve is released from the blocks [9, IS.

The clamping blocks I 9, l9 are also provided with slots 26, 26 extending entirely across them from the upper face thereof to a substantial distance below the lowermost portion of the sleevereceiving recess 23. When the two blocks l9, I!) are brought together with their respective grooves and 2! in alignment firmly to hold a sleeve between them, the pair of slots 26 of the respective blocks form a. single continuous slot extending diagonally through and across the sleevereceiving bore 22. The slot 26, 26 serves accurately to guide a saw blade 27, preferably a circular saw, as it is moved relatively to the blocks to sever the sleeve and form the pair of electrodes 28, 29, Fig. 4, having opposed diagonally cut and spaced ends and so suited to form an ion-trap.

After the matched pair of electrodes 28, 29 are [9, I9, any

be removed by a bufling or smoothing operation. As shown by comparison of Figs. 3 and 4, the length of the mark or scratch is such that a portion of it remains on each of the pair of electrodes 28 and 29 after their, severance from a common sleeve ID. These marks are of material assistance when the pair of electrodes are as- 1 sembled in an electron gun because facilitating positioning of them in their original and proper angular relation for which the trapping slot or gap 34 between them is of constant width between the opposed peripheries of the axially and angularly aligned electrodes 28, 29.

As shown in Fig. 8, and more clearly in Figs. 9 to 11, the integral peripheral ring I8 formed at the end of each ion-trapping electrode 28, 29 is received by the complementary grooved portions 38 of a pair of clamping ring members 3|. Each of the seini-circular ring members 3| is provided with wing extensions as projecting from opposite sides thereof and shaped to form the glide sections ii. In assembling the ion-trap, the adjacent ends of the wing extensions are secured to each other, as by welding, and the electrodes 28, 29 adjusted to proper position by sliding them along rods 42 embraced by the glide sections and by rotating them within the ring members 3! to proper angular position. The parts are then permanently held in place as by spot-welc'ing the ring members of each pair in the regions between the glide sections ll and the electrode-clamping section.

' Preferably, and as shown most clearly in Fig. 32 at the end of each of the trap electrodes 28, 29 is provided with a turned back rim 33 which nests between the mounting of the associated trap electrode 28 or 29 pair of clamping rrembers 3|. 7

The ion-trap electrodes 28, 29 are held to rods 42,-Fig. 11, in axial alignment with other cylindrical electrodes of the including the 2nd 35, the accelerating electrode 31, and the cathodegun assembly, Fig. 8, anode 35, the 1st anode grid assembly 38, with the apertures in discs 32 of the ion-trap electroces in alignment with the apertures of the discs 39 of the other electrodes.

It shall be understood that the invention is not limited to the particular construction disclosed and that changes may be made within the scope of V the appended claims.

'What is claimed is:

1. The method of making an ion-trap for an electron-gun comprising the steps of internally chamfering both ends of a metal sleeve, outwardly spreading and rolling each end of the sleeve to form an integral external mounting ring of larger diameter, longitudinally marking the sleeve, diagonally severing the sleeve within the limits of the marking to form a matched pair of ion-trap electrodes, and thereafter mounting said pair of electrodes in axially spaced alignment and in relative angular position for which their markings are in alignment.

'2, The method of making an ion-trap for an electron-gun comprising the steps of shaping each of both ends of a metal sleeve to form an external mounting ring of larger c'iameter, externally marking said sleeve longitudinally thereof, diagonally severing the sleeve Within limits of the marking to form a pair of ion-trap electrodes with aligning marks, and thereafter mounting said pair of electrodes in axially-spaced alignment and in relative angular position for which their markings are in alignment.

3. An ion-trap comprising a pair of tubular electrodes each having an integrally formed ring at one end and whose other end is diagonal to the axis of the electrode, and structure engaging said integral rings supporting said electrodes in spaced axial alignment and in angular position, the ga between the opposed diagonal ends being of constant width circumferentially of the trap.

4. An ion-trap comprising a pair of tubular electrodes each having an integrally formed bead extending peripherally thereof at one end, whose other end is c'iagonal to the axis of the electrode and to a mark extending longitudinally from said other end, and structure engaging said beads to support said electrodes in spaced axial alignment and with the longitudinal mark on each of the electrodes in alignment with the longitudinal mark on the other electroc'e to obtain constant width of the gap between the opposed diagonal ends of said electrodes.

5. An ion-trap for a cathode-ray tube comprising a pair of seamless tubular electrodes each having at one end thereof an integral flange and whose other end is diagonal to the axis of the structure embracing said flanges to support said electroc'es in spaced axial alignment and in relative angular position for which the gap between the opposed diagonal ends is of constant width circumferentially of the trap.

BENJAMIN M. NASE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

